In recent years, it is required to develop a small, high-performance battery as a power source of automobiles, personal computers, mobile phones, and tablet computers, etc. As to such a battery, development of an all-solid battery using a solid electrolyte is being aggressively carried out in parallel with an electrolyte battery using a liquid electrolyte.
In general, an all-solid battery has, as one of structural elements, an electrode active material layer containing an electrode active material and a solid electrolyte, etc. The electrode active material as used herein indicates a cathode active material in a positive electrode and an anode active material in a negative electrode.
The production of an electrode active material layer comprises kneading materials such as electrode active material and solid electrolyte to provide a mixture, and the kneading is often performed using a continuous extrusion kneader. At the time of kneading, aggregation of materials is prevented generally by applying a high shear force to the materials such as solid electrolyte and electrode active material.
For example, Patent Document 1 describes a continuous extrusion kneader for producing a mixture for electrode active material layer, comprising, from upstream to downstream, a first kneading section for kneading a solid electrolyte supplied from a first supply section, and a second kneading section for kneading the solid electrolyte kneaded in the first kneading section and an active material newly supplied from a second supply section.